Incineration



March 8, 1938. w. RAISCH 2,110,309

' INCINERATION Filed Nov. 12 1936 INVENTOR WILLIAM RAISCH BY fmg ATTORNEY Patented Mar. s, 1938 2,1103%- UNl'i'D STATES TE'FOFHQE 2,110,309 momsaa'riou William Raisch, New York, N. Y., assignor to Underpinning 85 Foundation 60., End, New York, N. 2., a corporation of New York Application November 12, 1936, Serial No. 110,419'

9 Claims. (oi; 110-42) This invention relates to incineration and more ly: around the edge of the partition and then particularly to improvements in tiered multipleoutwardly to ducts at the peripheral wall through hearth furnaces and to improvements in procwhich it flows upwardly to the nexthollow esses for drying and burning material of a high hearth or tothe hollow top of the furnace. The

moisture or volatile content by passing it downheat transfer to the interior of the drying sec-- 5 Wardly through a plurality of zones, gradually tion is obviously very complete and it may not be drying it in upper zones and finally burning it necessary to preheat the air before its passage in lower zones. into the drying section. 2

Although the apparatus and method of the In the drawing, Figure 1 is a view in vertical present invention are applicable to the treatment section of the apparatus of the present invention. 10 of many kinds of material, they are of particular Figure 2 is a fragmentary section on line 2 -2 value in drying and burning waste material such of Figure l. as garbage and sewage materials including sew- Figure 3 Be fragmentary section on line 3-3 age sludge and sewage screenings both of which of Figure l.

have a substantial moisture content. Referring to the drawing in which there is 15.

' The principal objects of the invention are to illustrated a preferred form of apparatus includprovide novel, advantageous and eiiective forms ing a multiple-hearth furnace Hl having a peof apparatus and processes adapted for treatment ripheral wall I l a hollow top I2 and hearths I3, of materials of the general character specified. l5, Hi, wi and 59 Of which the hearth Another object relates to improved means for forms the bottom of the furnace. In order to heating the interior of the drying section by use permi th dow wardmoveme t 0f he material. of the gases of combustion from the burning from hearth to. hearth the uppermost hearth l3 section. Another object of the invention relates is provided with one or more peripheral outlets to improved hearth construction for the drying 26, the hearth M is provided with a central outsection to enable better heat exchange between let 2i, the hearth i5 is provided with a peripheral 25 the waste gases of combustion and the air and outlet-22 equipped with a feeding device 23 forvapors in the drying section. A further object eed ng the material from the compartment relates to improved heat exchange means whereabove. the hearth 22 to the compartment below by heat from the combustion gases is supplied the hearth 22 which prevents the passage of gas to the interior of the drying section from the top between the two compartments, the hearth I6 is 1 and sides of the section but also from the upper provided with a central opening 2!, the hearth I1 and lower surfaces of the'hearth. is provided with one or more peripheral openings In carrying out the invention, use may be made 29, the hearth is is provided with a central openof a multiple-hearth furnace divided into an uping 2i andthe hearth 19 or bottom of the furper drying section and a lower burning secnace is provided with an outlet or chute 26 nor- 5. tion by a hearth provided with a device which really closed by a door or gate 25 urged to closfeeds material from the compartment above the ing position by weighted arm 26. Suitable gas dividing hearth to the next lower compartment seals around the shaft 3!] are provided at the without permitting the flow of gas therethrough. top l2 and the hearths l3, l5, I1 and I9. At the 40 .Air is supplied to the upper part of the drying top of the furnace, material is introduced into 40 section and passed downwardly therethrough and the uppermost compartment through a hopper then is passed from the bottom of the drying 21, a chute 280! passing through the hollow top 12 zone to the lower part of the burning section. and provided with a pivoted gate 28 normally The furnace may also have a hollow top through held in closed position by a weighted arm 29.

which the hot gases pass before final discharge Positioned substantially axially with reference 45 from the furnace. An. important feature of the to the furnace is a hollow shaft 30 carrying rabpresent invention relates to the passage of the bling devices which extend over the upper surhot gases from the burning section through one faces of said hearths, each of these rabbling deor more hollow hearths of the drying section ices constituting an arm 3i and blades 32 so and through a series of peripherally arranged inclined with the rabbling devices over the 50 ducts to upper hollow hearths or to the hollow hearths l3, l5, ll! and #9 so as to Work the matetop of the furnace, each hollow hearth being rial outwardly on these hearths, and so inclined so divided by a substantially horizontal partiabove the hcarths i l, 58 and l8 as to work the tion so that the gases will flow toward the center material toward the central openings 2|. The

along the lower side or the hearth, then upwardshait;3l3 may be operated in any suitable manner 55 as by means of a bevel gear 33 thereon, a bevel gear 34 meshing with the bevel gear 33 and a pulley 35 connectedwith the bevel gear 34 and operated from any suitable source of power.

The feeding device or valve 23 at the hearth I I5 may be of any suitable kind, but is here shown as made up of two feed screws, one of which, 36, feeds the material outwardly and the other of which, 31, receives the material from the screw 36 and works it inwardly to discharge'it into the compartment below the hearth IS. The screws 3 6 and 31'may be mounted on shafts 38 and 39 respectively and connected for driving in opposite directions by means of intermeshing gears 40 and 4|.

Air is introduced into the upper part of the drying section by means of a duct 42 and passes downwardly through the drying section, and then, laden with vapors of moisture and volatile materials, is passed through a duct 43 to the lower part ,of the' burning section, preferably to the lowermost compartments of the burning section.

From the upper part of the burning zone, the hot gases of combustion are passed through a duct 44 to the lowermost hollow hearth l4 of the drying section, then through the upper hearth l3 andto the hollow top from which they are discharged through a duct 45. Except for the positions of the outlets, the

-hearths I3. and I4 are very similar. The hearth I4 is hollow and midway between its upper and 'lowerwalls is provided with an annular partition 46 extending from the outside peripheral wall 'of the hollow hearth to a position somewhat short. of the chamber wall around the shaft 30 so that hot gases introduced into the hearth belowthe partition 46 will flow'inwardly along the bottom of the hearth, upwardly at the center of the hearth and then outwardly beneath the top wall,of the hearth. Proper spacing between the bottom wall of the hearth l4 and the partition 46 may be obtained by vices 41. Adjacent to the interior surface of the peripheral wall ll of the furnace, the upper .chamber'of the hearth I4 is connected with a plurality of ducts 48 extending upwardly and around a considerable portionof the periphery of the drying chamber which ducts communicate with alower compartment in hearth l 4'separated from the upper compartment therein by means of a central partition 49 supported from the lower wall of the hearth by means of suitable spacing devices 50. In this hearth as in the hearth I4 the hot gases of combustion are passed inwardly around the inner edge of the partition and then pass upwardly through a series of ducts 5| to the hollow top I2 of the furnace.

In order to aid in starting the furnace and to assure the proper temperature the furnace may be provided at suitable points ,with burners 52.

. Access to the different compartments may be had true spirit and scope of the invention.-

through doors 53.

Obviously the heat in the hot combustion gases is used very effectively in heating the interiorof thedrying section and the air therein. It may therefore be unnecessary to preheat the air supplied to the drying section.

It should be understood that various changes may be made and that various features may be used without others without departing from the Having thus described my invention, I claim:

1. In a tiered multiple-hearth furnace includ-' ing an intermediate hearth with a gas seal separating the furnace into an upper drying section in heat exchange use of suitable spacing de-.

hollow hearth and a partition therein dividing the hearth into a lower compartment, receiving the hot combustion gases and an upper compartment communicating with the lower compartment near the center of the hearth and receiving the hot gases from the lower compartment, and means for discharging the hot combustion gases from said upper compartment.

2. In a tiered multiple-hearth'furnace includ-' ing a peripheral wall, an intermediate hearth with a gas seal separating the furnace into an upper drying section and a lower burning section, means for supplying air to the drying section, means for passing air and vapors from the drying section to the burning section and means for discharging hot combustion gases from the burning section, means for heating the interior of the drying section by means of said hot combustion gases comprising a hollow furnace top, a hollow uppermost hearth and a partition therein dividing the hearth into a lower compartment receiving the hot combustion gases and an upper compartment communicating with the lower compartment near the center of the hearth and receiving the hot gases from the lower compartment, means for conducting the hot combustion gases from said upper compartment upwardly along the inner surface of said peripheral wall relationship with the interior of the furnace and discharging the same into said hollow top, and means for discharging the combustion gases from said hollow top.

3. In a tiered multiple-hearth furnace including a peripheral wall, an intermediate hearth with a gas seal separating the furnace into an upper drying section and alower burning section, means for supplying air to the drying section,

means for passing air and vapor from the drying uppermost hearth and a partition therein dividing the hearth into a lower compartment receiving the hot combustion gases and an upper compartment communicating with the lower compartment near the center of the hearth and receiving the hot gases from the lower compartment, ducts arranged around the inner surface of the peripheral wall for conducting the hot combustion gases from said upper compartment upwardly along the inner surface of said peripheral wall in heat exchange relationship with the interior of the furnace and discharging the same into said hollow top, and means for discharging the combustion gases from said hollow top. 4. In a tiered multiple-hearth'furnace including an intermediate hearth with a gas seal separating the furnace into an upper drying section and a lower burning section, means for supplying air to the drying section, means for passing air and vapor from the drying section to the burning section and means for discharging hot combustion gases from the burning section, means for heating the interior of the drying section by means of said hot combustion gases comprising a hollow'hearth and an annular parand. an upper compartment tition therein dividing the hearth into a lower compartment receiving the hot combustion gases communicating with the lower compartment near the center of the hearth around the inner edge of said annular partition and receiving the hot gases from the lower compartment, and means for discharging the hot combustion gases from said upper compartment.

5. In a tiered multiple hearth furnace including a peripheral wall, an intermediate hearth with a gas seal separating the furnace into an upper drying section and a lower burning section, means for supplying air to the drying section, means for passing air and vapor from the drying section, means for passing air and vapor from the drying section to the burning section and means for discharging hot combustion gases from the burning section, means for heating the interior of the drying section by means of said hot combustion gases comprising a plurality of hollow hearths, a partition in each hearth dividing the hearth into a lower compartment receiving the hot combustion gases and an upper compartment communicating with the lower compartment near the center of the hearth and receiving the hot gases from the lower compartment, means for conducting gases from the upper compartment of a lower hollow hearth to the lower compartment of the next higher hollow hearth, and means for discharging the hot combustion gases from the upper compartment of the uppermost hollow hearth.

6. In a tiered multiple-hearth furnace including an intermediate hearth with a gas seal separating the furnace into an upper drying section and a lower burning section, means for supplying air to the drying section, means for passing air and vapor from the drying section to the burning section and means for discharging hot combustion gases from the burning section, means for heating the interior of the drying section by means of said hot combustion gases comprising an annular hollow hearth and an annular partition therein dividing the hearth into a lower compartment receiving the hot combustion gases and an upper compartment communicating with the lower compartment near the inner edge of the hearth and receiving the hot gases from the lower compartment, and means for discharging the hot combustion gases from said upper compartment.

'7. The method which comprises passing material of high moisture content downwardly through a plurality of zones while first drying and then burning the same, temporarily retaining said material in each of a plurality of said zones, moving said material substantially horizontally through each of said zones by the application of a series of rabbling impulses thereto, preventing the direct passage of gases between two adjacent zones, thereby separating the zones into a drying group and a burning group, passing a stream of air downwardly through the zones of the drying group along the path of travel of the material, discharging air and vapor from the lower part of the drying group and introducing them into the lowermost burning zone, passing the gaseous products of combustion from one of the burning zones over one of the drying zones in heat exchanging relationship with the air and vapors therein but separated therefrom and then beneath the next higher drying zone in heat exchanging relationship therewith, and discharging the hot combustion gases from the drying zones.

8. The method which comprises passing material of high moisture content downwardly through a plurality of zones while first drying and then burning the same, temporarily retaining said material in each of a plurality of said zones, moving said material substantially horizontally through each of said zones by the application of a series of rabbling impulses thereto, preventing the direct passage of gases between two adjacent zones, thereby separating the zones into a drying group and a burning group, passing a stream of air downwardly through the zones of the drying group along the path of travel of the material, discharging air and vapor from the lower part of the drying group and introducing them into the lowermost burning zone, passing the gaseous products of combustion from one of the burning zones over one of the drying zones in heat exchanging relationship with the air and vapors therein but separated therefrom and then beneath the next higher drying zone in heat exchanging relationship therewith, and finally passing the hot gases over the uppermost drying zone and discharging them from the drying zones.

9. The method which comprises passing material of high moisturecontent downwardly through a plurality of zones while first drying and then burning the same, temporarily retaining said material in each of a plurality of said zones, moving said material substantially horizontally through each of said zones by the application of a series of rabbling impulses thereto, preventing the direct passage of gases between two adjacent zones thereby separating the zones into a drying group and a burning group, passing a stream of air downwardly through the zones of the drying group along the path of travel of the material discharging air and vapor from the lower part of the drying group and introducing them into the lowermost burning zone, passing the gaseous products of combustion from one of the burning zones over one of the drying zones in heat exchanging relationship with the air and vapors therein but separated therefrom and then beneath the next higher burning zone in heat exchanging relationship therewith, passing the hot gases upwardly around said next higher drying zone and then over the same in heat exchanging relationship therewith, and finally discharging said hot gases,

RAISCH. 

